In Kerbal Space Program, this corresponds to any anomaly that has been hidden in the game on the surfaces of bodies in the Kerbol System the Main Menu, in IVAs, and any other applicable area by the developers. This does not include bugs like terrain glitches.

This page contains spoilers, as you have already been warned. For any who wish to preserve the sense of exploration, please do not continue.

Although itself a terrain glitch, the Mohole (a large, steep vertical "tunnel" at Moho's north pole) could be considered an easter egg, since anomalous forces are present around its rim, which may well be deliberate, and the fact that the mohole has its own biome, the Northern Sinkhole. In the version 1.2 readme file, the changelog states that "Mohole given an empty PQSCity, which allows it to appear in KerbNet." suggesting the Mohole's are no longer glitches, but now permanent Easter Eggs.

Near the zero longitude meridian on Gilly, there is an anomalous "slot" in the terrain, which is about 2m x 1km in dimension. On approach, you can see stars in the slot. Touching the slot with a Kerbal on EVA or with a craft will destroy the Kerbal or the craft. It is not clear whether this is an intended Easter egg, or just a bug.

In the ocean just south of the KSC, about midway between land and the southern ice cap (about 30° 0′ 0″ S 80° 0′ 0″ W), engraved into the ocean floor is a giant smiley face, best seen from orbit or on a topography map like File:Kerbin heightmap.jpg. Also surprisingly it's really close to kerbin a lowest trench according to kerbal maps. Maybe there is some secret underwater down there?

The inland KSC at (20° 40′ 15″ N 146° 29′ 48″ W) actually has its own biomes, even including launch pad. if a flag is placed on it and you try to launch a rocket, it will make you remove the flag.

Magic Boulder - Missing since 0.18 - The magic boulder used to orbit Ike at an altitude of 15 km with zero eccentricity and an inclination of 80 degrees. The mesh (physical surface) for the magic boulder did not match its texture (visible surface) which could result in ships apparently digging into the surface with no ill effect. It would also cause ships to explode seemingly spontaneously, sometimes metres away from the surface, displaying "vesselname crashed into Magic Boulder" in the Flight Log. It also seemed to glow green as if radioactive, and there was a Monolith on its leading edge. The boulder had no gravity, did not appear in the map view and could not be targeted, much like any other easter egg, except in orbit. The Magic Boulder was re-added as a random asteroid as of 1.1.3 and cannot be found orbiting Ike, but can be found as an asteroid if you're lucky enough to track it. It's known to come in different colours: Pink, Orange, Blue, Red, Yellow and the good old green.

Easter Egg Narrative

In a forum post from late 2013,[1]Squad member Jeff C.(NovaSilisko) described an idea he had for connecting many easter eggs into a story concerning a civilization which predated the Kerbals. Experiments with interstellar travel resulted in the homeworld of this "precursor civilization" being flung out into an extremely distant orbit. Before they froze to death, they launched monoliths and other messages onto many planets and moons in hopes of seeding intelligent life. Instead, they created Kerbals, not-so-intelligent life.

The planet would not show up in any map and would be too distant to be observed with a telescope, making locating it by chance nearly impossible. However, players would be able to find transmitters beaming out SSTV signals on various bodies, each one of which would provide part of the orbital parameters necessary to locate it. The planet would be a bit smaller than Kerbin, covered in ruined cities and frozen oceans, and perpetually in twilight due to being so far from Kerbol.

The only element of this narrative which made it into the game is the SSTV transmitter on Duna, which transmits an image originally intended to depict 4 members of the precursor civilization standing on their homeworld, with the logo of their government. Had the narrative story been completed, it would also have contained part of the orbital parameters. Because the story was never implemented into the game, this explanation for the SSTV signal's imagery is arguably non-canon.[2]

Miscellaneous

While not easter eggs per se, the exact geographical poles of most bodies have highly unusual topography, usually making them inaccessible, see terrain glitch.

An average of the skin color in Kerbal arm textures compared to the rumored colors

The color of the Kerbals' skin is close to is #BADA55 () in hexadecimal but does not match it exactly. The hexadecimal RGB value spells like “badass” in leetspeek. Some say #84D455 () is the color of a Kerbal which is even further away than #BADA55. This connection is rumored, because Kerbals can have a BadS flag, which is usually interpreted as badass.

Some of the cockpits have post-it notes and other humorous writings inside them. The writing is somewhat blurry on normal settings and hard to read, but still legible. For transcripts of the notes, see the respective part pages.

When double-clicked on the screen which says "docking mode" in the mk1 cockpit, the IVA view changes to show upwards through the window on the top-back of the cockpit with a flight console. This suggests Kerbals can leave (or rotate?) their seats to make it easier to dock. It should be designed to be used with Inline Clamp-O-Tron.

The FL-T200 Fuel Tank has a very faint drawing on it which can just about be observed when fully zoomed in. The drawing becomes more visible during re-entry and appears to depict a failed re-entry procedure which has then been crossed out.

The Mk3 to Mk2 Adapter has the word "Kurvy" written on it, most likely a reference to its shape.

The EAS-4 Strut Connector has a cost of 42 an obvious reference to The Hitchhiker's guide to the galaxy's answer to the ultimate question.

The Telus Mobility Enhancer is similar to the ladder on the A-10 "Warthog" Close Ground Support Plane.

The LY series landing gear is a dual reference to Akron, Ohio based "Goodyear Tire & Rubber Company" and Buzz Lightyear from the Toy Story Franchise. On the tires,"Lightyear" is written.

During April fools, Nyan Cat can be seen flying across the screen. This is confirmed in 1.0.5-1.1[3]

As of 1.2, there are many more 'witty loading hints'.

Main Menu

One of the two main menu images is that of a Kerbal standing on the Mun's surface, with Kerbin in the background. There is a 1 in 40 chance that a sand castle made of Mun dust can be seen near his feet.

The Mun dust castle.

Scenarios

The Kerbal XX orbiting Duna

During the Space Station One scenario, by zooming out far enough to show the planetary map, a ship by the name of 'Kerbal XX' can be seen orbiting around Duna in a near-equatorial orbit (as of 0.23)

Patcher

If you look into the patcher log, before updating, the log says "HOLD ON TO YOUR BUTTS!"